82 ISCHNOCHITON. 



I. viRGATUs Reeve. (Vol. XIV, p. 78.) 



This is a smooth-scaled Ischnochiton, grouping with /, smarag- 

 diiius and I. lentiginosns. 



I. LENTiGiNOSus Sowerbj. 



See Vol. XIV, p. 135. This species has been rediscovered by Dr. 

 J. C. Cox at Port Hacking, N. S. Wales. It is a smooth form, with 

 convex, polished girdle-scales, and is remarkable for the coloration 

 of blue spots on an orange, orange-brown or olivaceous ground. It 

 is apparently distinct from /. cyaneopundatus Kr. 



Section Heterozona Cpr. (Vol. XIV, p. 65). 

 H. CARiosA Cpr. PI. 14, fig. 8. 



A figure is here given of a larger specimen from the collection of 

 the Geological Survey of Canada. It has the girdle scales more 

 unequal than shown in pi. 24, fig. 21, and they are narrower and 

 more elongated. The granulation of the central areas shown in fig. 

 20 is much too coarse. A considerable number of specimens received 

 from Dr. J. C. Cox, show great variation in the girdle covering, fully 

 covering the differences between figs. 21 and 23 of pi. 24. 



Section Lepidozona Pilsbry. 



Ischnochitons having the girdle-scales strongly convex, smooth or 

 Striated ; valves with a lamina across the sinus, separated from the 

 sutural laminse by a notch, and often denticulate ; teeth subrugose; 

 mucro low, inconspicuous, nearly flat, subcentral. Sculpture consist- 

 ing of pustules or graniferous ribs on lateral areas and end valves, 

 and longitudinal riblets on the central areas, the interstices usually 

 latticed. 



This section, as here amended, is a very useful one, comprising 

 Ischnochitons of the mertensii group on the west coast of America, 

 and the coreanicus group on Sino-Japonic shores. 



I. cuLTRATUS Cpr. PI. 17, figs. 57, 58, 59. 



The original description is given on page 131 of vol. XIV. 



The shell is rather elevated and rather sharply carinated, the side- 

 slopes nearly straight. Color whitish or light green, indistinctly 

 mottled and spotted with dark green. 



Intermediate valves squared, not in the least beaked. Lateral 

 areas raised, having four lotv rounded ribs separated by rather acute 

 interstices, each rib bearing widely fpaeed, elevated pustules of a red- 

 dish-brown color, the posterior border of the valve having an addi- 



